diff options
Diffstat (limited to 'ipc/namespace.c')
| -rw-r--r-- | ipc/namespace.c | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/ipc/namespace.c b/ipc/namespace.c index 1b967655eb35..9171d948751e 100644 --- a/ipc/namespace.c +++ b/ipc/namespace.c @@ -20,10 +20,20 @@ static struct ipc_namespace *clone_ipc_ns(struct ipc_namespace *old_ns) if (ns == NULL) return ERR_PTR(-ENOMEM); + atomic_inc(&nr_ipc_ns); + sem_init_ns(ns); msg_init_ns(ns); shm_init_ns(ns); + /* + * msgmni has already been computed for the new ipc ns. + * Thus, do the ipcns creation notification before registering that + * new ipcns in the chain. + */ + ipcns_notify(IPCNS_CREATED); + register_ipcns_notifier(ns); + kref_init(&ns->kref); return ns; } @@ -79,8 +89,24 @@ void free_ipc_ns(struct kref *kref) struct ipc_namespace *ns; ns = container_of(kref, struct ipc_namespace, kref); + /* + * Unregistering the hotplug notifier at the beginning guarantees + * that the ipc namespace won't be freed while we are inside the + * callback routine. Since the blocking_notifier_chain_XXX routines + * hold a rw lock on the notifier list, unregister_ipcns_notifier() + * won't take the rw lock before blocking_notifier_call_chain() has + * released the rd lock. + */ + unregister_ipcns_notifier(ns); sem_exit_ns(ns); msg_exit_ns(ns); shm_exit_ns(ns); kfree(ns); + atomic_dec(&nr_ipc_ns); + + /* + * Do the ipcns removal notification after decrementing nr_ipc_ns in + * order to have a correct value when recomputing msgmni. + */ + ipcns_notify(IPCNS_REMOVED); } |